Academic literature on the topic 'Drop hammer rig'

A recent upgrading of a drop hammer rig was carried out and a series of calibration tests established the energy losses in the existing anvil. Both the test results and the mathematical modelling showed that significant energy losses would occur at high impact loads. An alternative anvil design considerably reduced the energy losses and improved the performance of the drop hammer rig.

This article studies the perforation of mild steel square and rectangular plates struck normally by cylindrical projectiles having blunt, hemispherical, and conical impact faces. Experimental results are obtained in a drop hammer rig for the perforation of 4mm and 8mm thick plates struck by relatively heavy projectiles weighing between 11.9kg and 200kg and traveling at an initial velocity up to about 13m∕s. The plates were struck at the center and at several positions near the fully clamped supports. The effect of the aspect ratio on the perforation energies of rectangular plates is examined, and comparisons are made with the perforation behavior of fully clamped circular plates. The predictions of several empirical equations are compared with the corresponding experimental values of the perforation energies. Simple design equations are also presented for predicting the maximum permanent transverse displacements of square plates prior to any cracking or perforation.

The startup of rocket engine turbopumps is generally performed only in a few seconds. It implies that these pumps reach their nominal operating conditions after only a few rotations. During these first rotations of the blades, the flow evolution in the pump is governed by transient phenomena, based mainly on the flow rate and rotation speed evolution. These phenomena progressively become negligible when the steady behavior is reached. The pump transient behavior induces significant pressure fluctuations, which may result in partial flow vaporization, i.e., cavitation. An existing experimental test rig has been updated in the LML Laboratory (Lille, France) for the startups of a centrifugal pump. The study focuses on the cavitation induced during the pump startup. Instantaneous measurement of torque, flow rate, inlet and outlet unsteady pressures, and pump rotation velocity enable to characterize the pump behavior during rapid starting periods. Three different types of fast startup behaviors have been identified. According to the final operating point, the startup is characterized either by a single drop of the delivery static pressure, by several low-frequency drops, or by a water hammer phenomenon that can be observed in both the inlet and outlet of the pump. A physical analysis is proposed to explain these three different types of transient flow behavior.

Abstract The consideration of the temporal and electromyographic (EMG) characteristics of stretch-shortening cycles (SSC) are crucial for the conceptualization of discipline-specific testing and training. Since leg muscles are first stretched (eccentric) and then contracted (concentric) during rowing, it can be assumed that the entire muscle tendon complex performs a SSC. Thus, it should be elucidated whether the rowing cycle can be attributed to either a slow or fast SSC. Therefore, EMG of the vastus medialis and gastrocnemius were captured (n = 10, 22.8 ± 3.1 years, 190 ± 6 cm, 82.1 ± 9.8 kg) during (single scull) rowing and subsequently compared to typical slow (countermovement jump, CMJ) and fast (drop jump, DJ) SSCs. The elapsed time between the EMG onset and the start of the eccentric phase was monitored. The pre-activation phase (PRE, before the start of the eccentric phase) and the reflex-induced activation phase (RIA 30–120 ms after the start of the eccentric phase) have been classified. Notable muscular activity was observed during DJ before the start of the eccentric phase (PRE) as well as during RIA. In contrast, neither CMJ nor rowing revealed any EMG-activity in these two phases. Interestingly, CMJ and race-specific rowing showed an EMG-onset during the eccentric phase. We conclude that rowing is more attributable to a slow SSC and implies that fast SSC does not reflect discipline specific muscle action and could hamper rowing-performance-enhancement.

February 15, 1999 THE DIGITAL EXAM digital was such a sanitary hi-tech word until my urologist snuck up from behind and gave me the bird shocked and taken back I try to ignore the painful experience by pondering the conundrum of homosexuality there had to be more to it than that "You can get dressed now" was the good doctor’s way of saying "Pull up your pants, Dude, and I’ll see you back in my office." but his casual demeanor seemed to exude foreboding "There is a stiffness in the gland demanding further examination. I’d like to schedule a blood test, ultrasound and biopsy." the doctor’s lips kept moving but I couldn’t hear him through the sheet of white fear that guillotined between us CANCER! The big C! Me? I spent the rest of that day up to my genitals in the grave I was digging. Hamlet gazing full into the face of the skull "Alas poor Yorick, I knew him well, Horatio. Before scalpel took gland. Back when he sang in a bass baritone." desperate for encouragement I turn to the illustrated brochure the informative flyer detailing the upcoming procedure where in the ultrasound and biopsy probe resembled the head of a black water moccasin baring its fang "Dang!" says I jumping back relief came 36 hours later something about the PSA blood test the prostate specific-antigen results leading the doctor to now suspect infection prescribing an antibiotic of course five weeks from now the FOLLOW-UP APPOINTMENT! and as the date approaches tension will build like in those Mel Gibson Lethal Weapon films when you know there’s a snake in the grass and Danny Glover isn’t there to cover your ass *** April 2, 1999 As it turns out, at the follow-up appointment, things had worsened so the biopsy and bone scan were re-scheduled and it was discovered that I do have incurable metastatic advanced prostate cancer. Of course the doctor is most optimistic about all the new and miraculous treatments available. But before I go into that, I want you to know that I find myself experiencing a strange and wonderful kind of peace. Hell, I’ve lived 70 years already — done exactly what I wanted to do with my life. All worthwhile dreams have come true. Made my living since 1968 as a "Performance Poet" — Billie Barbara and I have been together for 47 years — growing closer with each passing day. We have four great kids, five neat and nifty grandchildren. All things considered, I’ve been truly blessed and whether my departure date is next year or 15 years from now I’m determined not to wreck my life by doing a lousy job with my death. LIKE HAROLD / LIKE HOWARD like Harold I don’t want to blow my death I don’t want to see a lifetime of pluck and courage rubbed out by five weeks of whiny fractious behavior granted Harold’s was a scary way to go from diagnosis to last breath the cancer moving fast but five weeks of bitching and moaning was more than enough to erase every trace of a man I have wanted to emulate his wife sending word that even she can’t remember what he was like before his undignified departure no — I don’t want to go like Harold like Howard let me come swimming up out of the deepening coma face serene as if seen through undisturbed water breaking the surface to eagerly take the hand of bedside well wishers unexpected behavior I must admit as Howard has always been a world class hypochondriac second only to me the two of us able to sit for hours discussing the subtle shade of a mole turning each other on with long drawn out organ recitals in the end one would have thought such a legendary self centered soul would cower and fold up completely like Harold but no — when my time comes let me go sweetly like Howard *** April 7, 1999 The treatment was decided upon. Next Monday, the good Doctor is going to pit my apricots. From here on the Sultan can rest easy when Masten hangs with his harem. Prognosis good. No more testosterone - no more growth. Now, don’t get me wrong, I’m not looking forward to giving up the family jewels. I must say that over the years they’ve done me proud and to be totally honest I don’t think Billie Barbara will be all that disappointed either. I’m told that Viagra will help in this area., However, I’m also told that the drug is very expensive. Something like twelve bucks a pop. But hell, Billie Barbara and I can afford twenty four dollars a year.. Some thoughts the morning of— Yesterday I did a program for the Unitarian Society of Livermore. About 60 people. I had a bet with the fellow who introduced me, that at least 7 out of the 60 would come up after the reading (which would include my recent prostate musings) and share a personal war story about prostate cancer. I was right. Exactly 7 approached with an encouraging tale about themselves, a husband, a brother, a son. I was told to prepare myself for hot flashes and water retention. To which Billie Barbara said "Join the club!" I ended the presentation with one of those inspirational poetic moments. A hot flash, if you will. "It just occurred to me," I said, " I’m going to get rich selling a bumper sticker I just thought of — REAL MEN DON’T NEED BALLS A couple of days after the event The Community Hospital of the Monterey Peninsula is referred to as CHOMP, and the afternoon of April 12th I must say this august institution certainly lived up to it’s name. The waiting room in the Out Patient Wing is an event unto itself. Patients huddled together with friends and family, everyone speaking in hushed voices. The doomed keeping a wary eye on the ominous swinging doors, where a big tough looking nurse appeared from time to time shouting: NEXT! Actually the woman was quite sweet and mild mannered, enunciating each patient’s name in a calm friendly manner. But waiting to have done to me what was going to be done to me - the chilling word "NEXT!" is what I heard and "Out Patient Wing" certainly seemed a misnomer to me. Wasn’t the "Out-Patient Wing" where you went to have splinters removed? Of course I knew better, because in the pre-op interview the young interviewer, upon reading "Bilateral Orchiectomy" winced visibly, exclaiming under her breath "Bummer!" I recently came across this haiku — bilateral orchiectomy the sound a patient makes when he learns what it is Our daughter April lives in New York and couldn’t join the Waiting Room rooting section so as her stand in she sent her best friend Molly Williams. Now, Molly works as a veterinarian in a local animal shelter and a when I told her my operation was supposed to take no more than half an hour, she laughed: "Heck Ric, I’ll do it in five minutes and not even use gloves." NEXT! My turn to be led through those swinging doors, pitifully looking back over my shoulder. Wife, family and friends, bravely giving me the thumbs up. Things blur and run together after that. I do remember telling the nurse who was prepping me that I was afraid of being put to sleep. "Not to worry" she said, I’d have a chance to express these fears to the anesthetist before the operation would begin. And as promised the man did drop by to assure me that I would get a little something to ease my anxiety before he put me under. When the moment finally arrived, he said that I might feel a slight prick as he gave me the relaxant. Of course, that is the last thing I remember - the prick! Obviously, I‘d been suckered in by the mask man’s modus operandi. On the other side of this I surface to begin the waiting. WAITING for the catheter to be removed — for the incision to heal — WAITING to see if the pain subsides and I can loose the cane — WAITING to learn if my PSA will respond to treatment. Waiting—waiting—waiting—and I’ve never been a cheerful waiter. *** May 7, 1999 The doctor tells me I must keep taking Casodex— one a day at eleven dollars a cap - for the rest of my life. And no more doctor freebees. No wonder the listed side effect of this pricey medication is depression. But the recent funk I’ve fallen into is much deeper than dollars and cents. In the past I’ve had my share of operations and illnesses and always during the recuperation I could look forward to being my old self again. But not this time .... Not this time. Funny bumper stickers can only hold reality at bay for a short while. And anyway Billie had me remove the homemade REAL MEN DON’T NEED BALLS bumper sticker from the back of our car — She didn’t like the dirty looks she got while driving around town alone. *** Eight months later BILATERAL ORCHECTOMY never could look up words in the dictionary in a high school assignment writing an autobiography I described my self as a unique person scribbled in the margin the teachers correction fairly chortled "unique" not "eunuch" how could he have known that one day I would actually become a misspelling backed against the wall by advanced prostate cancer I chose the operation over the enormous ongoing expense of chemical castration "No big deal." I thought at the time what’s the difference they both add up to the same thing but in the movies these days during the hot gratuitous sex scene I yawn…bored... wishing they’d quit dicking around and get on with the plot and on TV the buxom cuties that titillate around the products certainly arn’t selling me anything I realize now that although it would probably kill them the guys who went chemical still have an option I don’t philosophically I’m the same person but biologically I ‘m like the picture puzzle our family traditionally puts together over the holidays the French impressionist rendition of a flower shop interior in all it’s bright colorful confusion this season I didn’t work the puzzle quite as enthusiastically... and for good reason this year I know pieces are missing where the orchids used to be "So?" says I to myself "You’re still here to smell the roses." *** January 13, 2000 Real bad news! At the third routine follow-up appointment. My urologist informs me that my PSA has started rising again. The orchectomy and Casodex are no longer keeping the cancer in remission. In the vernacular, I have become "hormone refractory" and there was nothing more he, as a urologist could do for me. An appointment with a local oncologist was arranged and another bone scan scheduled. The "T" word having finally been said the ostrich pulled his head from the sand and began looking around. Knowing what I know now, I’m still annoyed at my urologist for not telling me when I was first diagnosed to either join a support group and radically change my diet or find another urologist. I immediately did both - becoming vegan and finding help on-line as well as at the local Prostate Cancer Support Group. This during the endless eighteen day wait before the oncologist could fit me in. *** IRON SOCKS time now for a bit of reverse prejudice I once purchased some stockings called "Iron Socks" guaranteed to last for five years they lasted ten! but when I went back for another pair the clerk had never heard of them as a cancer survivor… so far in an over populated world I consider the multi-billion dollar medical and pharmaceutical industries realizing that there is absolutely no incentive to come up with a permanent cure *** From here on, I’ll let the poems document the part of the journey that brings us up to the present. A place where I can say — spiritually speaking, that the best thing that ever happened to me is metastatic hormone refractory advanced prostate cancer. *** SUPPORT GROUPS included in this close fraternity... in this room full of brotherly love I wonder where I’ve been for the last 11 months no — that’s not quite right… I know where I’ve been I’ve been in denial after the shock of diagnosis the rude indignity of castration the quick fix of a Casodex why would I want to hang out with a bunch of old duffers dying of prostate cancer? ignoring the fact that everybody dies we all know it but few of us believe it those who do, however rack up more precious moments than the entire citizenry of the fools paradise not to mention studies showing that those who do choose to join a support group on average live years longer than the stiff upper lip recluse and while I’m on the subject I wonder where I’d be without the internet and the dear supportive spirits met there in cyber-space a place where aid care and concern are not determined by age, gender, race, physical appearance, economic situation or geological location and this from a die-hard like me who not ten years ago held the computer in great disdain convinced that poetry should be composed on the back of envelopes with a blunt pencil while riding on trains thank god I’m past these hang-ups because without a support system I doubt if this recent malignant flare-up could have been withstood how terrifying… the thought of being at my writing desk alone… disconnected typing out memos to myself on my dead father’s ancient Underwood *** PC SPES in the sea that is me the hormone blockade fails my urologist handing me over to a young oncologist who recently began practicing locally having retired from the stainless steel and white enamel of the high tech Stanford medical machine in the examination room numbly thumbing through a magazine I wait expecting to be treated like a link of sausage another appointment ground out in a fifteen minute interval what I got was an 18th century throw back a hands-on horse and buggy physician with seemingly all the time in the world it was decided that for the next three weeks (between blood tests) all treatment would cease to determine how my PSA was behaving this done, at the next appointment the next step would be decided upon and after more than an hour of genial give and take with every question answered all options covered it was I who stood up first to go for me a most unique experience in the annals of the modern medicine show however condemned to three weeks in limbo knowing the cancer was growing had me going online reaching out into cyberspace to see what I could find and what I found was PC SPES a botanical herbal alternative medicine well documented and researched but not approved by the FDA aware that the treatment was not one my doctor had mentioned (I have since learned that to do so would make him legally vulnerable) I decided to give it a try on my own sending off for a ten day supply taking the first dose as close after the second blood test as I could two days later back in the doctors office I confess expecting a slap on the wrist instead I receive a bouquet for holding off until after the second PSA then taking the PC SPES container from my hand and like a Native American medicine man he holds it high over his head shaking it "Okay then, this approach gets the first ride!" at the receptionist desk scheduling my next appointment I thought about how difficult it must be out here on the frontier practicing medicine with your hands tied *** PREJUDICE "It's a jungle out there!" Dr. J. George Taylor was fond of saying "And all chiropractors are quacks! Manipulating pocket pickers!" the old physician exposing his daughter to a prejudice so infectious I suspect it became part of her DNA and she a wannabe doctor herself infects me her son with the notion that if it wasn’t performed or prescribed by a licensed M.D. it had to be Medicine Show hoopla or snake oil elixir certainly today’s countless array of practitioners and patent remedies has both of them spinning in their grave but Ma you and Grandpa never heard the words hormone-refractory even the great white hunters of our prestigious cancer clinics don't know how to stop the tiger that is stalking me and so with a PSA rising again to 11.9 I get my oncologist to let me try PC SPES a Chinese herbal formula yes, the desperate do become gullible me, reading and re-reading the promotional material dutifully dosing myself between blood tests and this against the smirk of disapproval mother and grandfather wagging their heads in unison: "It won’t work." "It won’t work." having condemned myself beforehand the moment of truth finally arrives I pace the floor nervously the doctor appears at the door "How does it feel to be a man with a PSA falling to 4.8?" it seems that for the time being at least the tiger is content to play a waiting game which is simply great! Mother tell Grandpa I just may escape our families bigotry before it’s too late *** HELPLINE HARRY "Hi, how are you?" these days I'm never sure how to field routine grounders like this am I simply being greeted? or does the greeter actually want a list of grisly medical details my wife says it's easy she just waits to see if the "How is he?" is followed by a hushed "I mean… really?" for the former a simple "Fine, and how are you?" will do for the latter the news isn't great indications are that the miracle herbal treatment is beginning to fail my oncologist offering up a confusing array of clinical trials and treatments that flirt seductively but speak in a foreign language I don't fully understand so Harry, once again I call on you a savvy old tanker who has maneuvered his battle scared machine through years of malignant mine fields and metastatic mortar attacks true five star Generals know much about winning wars and such but the Command Post is usually so far removed from the front lines I suspect they haven't a clue as to what the dog-faces are going through down here in the trenches it's the seasoned campaigners who have my ear the tough tenacious lovable old survivors like you *** "POOR DEVIL!" in my early twenties I went along with Dylan Thomas boasting that I wanted to go out not gently but raging shaking my fist staring death down however this daring statement was somewhat revised when in my forties I realized that death does the staring I do the down so I began hoping it would happen to me like it happened to the sentry in all those John Wayne Fort Apache movies found dead in the morning face down — an arrow in the back "Poor devil." the Sergeant always said "Never knew what hit him." at the time I liked that... the end taking me completely by surprise the bravado left in the hands of a hard drinking Welshman still wet behind the ears older and wiser now over seventy and with a terminal disease the only thing right about what the Sergeant said was the "Poor devil" part "Poor devil" never used an opening to tell loved ones he loved them never seized the opportunity to give praise for the sun rise or drink in a sunset moment after moment passing him by while he marched through life staring straight ahead believing in tomorrow "Poor devil!" how much fuller richer and pleasing life becomes when you are lucky enough to see the arrow coming *** END LINE (Dedicated to Jim Fulks.) I’ve always been a yin / yang - life / death - up / down clear / blur - front / back kind of guy my own peculiar duality being philosopher slash hypochondriac win win characteristics when you’ve been diagnosed with advanced prostate cancer finally the hypochondriac has something more than windmills to tilt with the philosopher arming himself with exactly the proper petard an anonymous statement found in an e-mail message beneath the signature of a cancer survivor’s name a perfect end line wily and wise quote: I ask God: "How much time do I have before I die?" "Enough to make a difference." God replies *** STRUM lived experience taught them most of what they know so MD's treating men diagnosed with androgen-independent advanced prostate cancer tend to put us on death row and taking the past into account this negativity is understandable… these good hearted doctors watching us come and go honestly doing what they can like kindly prison guards attempting to make the life we have left as pleasant as possible to be otherwise a physician would have to be a bit delusional evangelical even… to work so diligently for and believe so completely in the last minute reprieve for those of us confined on cell block PC doing time with an executioner stalking it is exhilarating to find an oncologist willing to fly in the face of history refusing to call the likes of me "Dead man walking." *** BAG OF WOE there are always moments when I can almost hear the reader asking: "How can you use that as grist for your poetry mill? How can you dwell on such private property, at least without masking the details?" well... for the feedback of course the war stories that my stories prompt you to tell but perhaps the question can best be answered by the ‘bag of woe’ parable the "Once Upon a Time" tale about the troubled village of Contrary its harried citizens and the magical mystical miracle worker who showed up one dreary day saying: I am aware of your torment and woe and I am here to lighten your load! he then instructed the beleaguered citizens to go home and rummage through their harried lives bag up your troubles he said both large and small stuff them all in a sack and drag them down to the town square and stack them around on the wall and when everyone was back and every bag was there the magical mystical miracle worker said: "It’s true, just as I promised. You won’t have to take your sack of troubles home leave it behind when you go however, you will have to take along somebody’s bag of woe so the citizens of Contrary all went to find their own bag and shouldering the load discovered that it was magically and mystically much easier to carry --- End ---

Concrete is the most broadly used material in construction worldwide and Reactive Powder Concrete (RPC, a type of ultra high performance concrete) is a relatively new member of the concrete family. In this work the critical parameters of RPC mix design are investigated and the mix design is explored through a program of concrete casting and testing. Owing to the enhanced microstructure of RPC, porosity and permeability can be significantly decreased in the concrete matrix. This benefits the durability characteristics of RPC elements resulting in a longer service life with less maintenance costs than conventional concrete. It has been used for high integrity radiation waste material containers because of its low permeability and durability. Fibre reinforced RPC is also ideal for use in long span and thin shell structural elements without traditional reinforcement because of its advantageous flexural strength. Moreover, due to improved impact resistance, RPC can be widely employed in piers of bridges, military construction and blast protection. There is no standard approach to assessing the impact resistance of concrete. This investigation utilises relatively well accepted impact equipment to evaluate the mechanical properties of RPC under dynamic loading. The compressive and flexural tensile strengths of plain and fibre reinforced RPC are investigated using a variety of specimens and apparatus. The dynamic increase factor (DIF) is evaluated to indicate the strain rate sensitivity of the compressive and flexural strength.

In recent years wheel impact loads have become a very important topic in the railroad industry due to operational and safety concerns. Much attention has been given to the level of condemnable wheel impact load as determined by wayside detection systems, and to the root causes of tread defects that lead to these wheel impacts. This paper describes physical testing of a wheelset in an instrumented drop hammer system to examine the effects of impact loading on resultant stress levels at various locations on a wheel’s surface. The drop hammer, typically used for evaluation of draft gears, is located at ASF-Keystone in Camp Hill, PA, and can impart dynamic loads up to a maximum of 2,000 kips, which is well in excess of typical wheel impact loads recorded by wayside impact detection systems. Impact loads for drop hammer wheel testing were generally confined to a maximum of approximately 200 kips. Finite element analysis (FEA) modeling using only mechanical tread loading was conducted to determine the high stress locations for the wheel design and to correlate strain gauge results for static loading on the wheel. The instrumented drop hammer used for wheel impact testing is described, and wheel strain gauge issues are discussed. Vertical split rim wheel failures are described and are briefly reviewed. The implications of impact loading for vertical split rim wheel failures are discussed and recommendations for future work are offered.